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Troubleshooting with Indicators Section 8-1
8-1 Troubleshooting with Indicators
The indicators on the Ethernet Unit can be used to troubleshoot some error.
The probable cause and correction for errors that can be determined from the
LINK, HOST, RUN, ERC, and ERH indicators are listed in the following table.
RUN ERC ERH LNK HOST Probably cause Correction
Not lit Not lit Not lit --- --- Power is not being supplied to the CPU
Unit or the power supply voltage is too
low.
Supply power.
Make sure that the correct voltage is
being supplied.
The Ethernet Unit is faulty. Replace the Ethernet Unit.
The CPU Unit or Backplane is faulty. Replace the CPU Unit or the Back-
plane.
The mounting screws on the Ethernet
Unit are loose (CS Series) or the sliders
are not properly locked into place (CJ
Series).
Tighten the mounting screws to the
specified torque (CS Series) or lock
the sliders into place (CJ Series).
Not lit Lit Not lit --- --- The node address is set outside the cor-
rect range on the rotary switches.
Set the node address to between 01
and FE Hex.
The Ethernet Unit is faulty. Restart the PLC. If the problem per-
sists, replace the Ethernet Unit.
Not lit Not lit Lit --- --- The unit number on the Ethernet Unit is
not set correctly on the rotary switch.
Correct the unit number setting.
The I/O tables are not registered in the
CPU Unit.
Register the I/O tables.
The same unit number is being used on
another Unit as well.
Correct the unit number.
The CPU Unit is faulty. Restart the CPU Unit. If the problem
persists, replace the CPU Unit.
Lit --- --- Not lit --- There is no communications link with the
hub.
If power is not turned ON to the hub,
turn it ON.
If there is crossed cable between the
Ethernet Unit and the hub, use
straight cable.
Lit --- Lit --- --- There is a mistake in the Unit Setup or
routing tables.
Read the error history and correct
the data that is causing the error. If
the problem persists, replace the
CPU Unit.
Memory in the CPU Unit is faulty. Restart the CPU Unit. If the problem
persists, replace the CPU Unit.
The CPU Unit is faulty. Restart the CPU Unit. If the problem
persists, replace the CPU Unit.
Lit There is a mistake in the settings for a
server (DNS, SMTP, POP3, or SNTP) in
the Unit Setup.
Read the error status and history
and correct the data that is causing
the error. If the problem persists,
replace the CPU Unit.
Not lit --- Lit An error occurred in communications with
the server.
Inspect the communications path
(Ethernet Unit, cable connections,
hub, router, server), and correct the
situation that is causing the error.
Lit Lit --- --- --- An error occurred in EEPROM. Restart the PLC. If the problem per-
sists, replace the Ethernet Unit.
